Adaptive mechanisms of plants against salt stress and salt shock

Salinization process occurs when soil is contaminated with salt, which consequently influences plant growth and development leading to reduction in yield of many food crops. Responding to a higher salt concentration than the normal range can result in plant developing complex physiological traits and activation of stress-related genes and metabolic pathways. Many studies have been carried out by different research groups to understand adaptive mechanism in many plant species towards salinity stress. However, different methods of sodium chloride (NaCl) applications definitely give different responses and adaptive mechanisms towards the increase in salinity. Gradual increase in NaCl application causes the plant to have salt stress or osmotic stress, while single step and high concentration of NaCl may result in salt shock or osmotic shock. Osmotic shock can cause cell plasmolysis and leakage of osmolytes in plant. Also, the gene expression pattern is influenced by the type of methods used in increasing the salinity. Therefore, this chapter discusses the adaptive mechanism in plant responding to both types of salinity increment, which include the morphological changes of plant roots and aerial parts, involvement of signalling molecules in stress perception and regulatory networks and production of osmolyte and osmoprotective proteins

Two-component spike nanoparticle vaccine protects macaques from SARS-CoV-2 infection

Brouwer et al. present preclinical evidence in support of a COVID-19 vaccine candidate, designed as a self-assembling two-component protein nanoparticle displaying multiple copies of the SARS-CoV-2 spike protein, which induces strong neutralizing antibody responses and protects from high-dose SARS-CoV-2 challenge.The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is continuing to disrupt personal lives, global healthcare systems, and economies. Hence, there is an urgent need for a vaccine that prevents viral infection, transmission, and disease. Here, we present a two-component protein-based nanoparticle vaccine that displays multiple copies of the SARS-CoV-2 spike protein. Immunization studies show that this vaccine induces potent neutralizing antibody responses in mice, rabbits, and cynomolgus macaques. The vaccine-induced immunity protects macaques against a high-dose challenge, resulting in strongly reduced viral infection and replication i

Influence of anionic vacancies on the conductivity of La 9.33Si6-xAlxO26-x/2 oxide conductors with an oxyapatite structure

Al-doped oxyapatite-type lanthanum silicates La9.33Si 6-xAlxO26-x/2□x/2 (x = 0, 0.4, 0.8 and 1) powders have been prepared by the solid state reaction at high temperature in order to determine the influence of anionic vacancies on the electrical properties of the material. The crystal structure and properties of La9.33Si6-xAlxO 26-x/2□x/2 powders have been studied by X-ray diffraction (XRD) patterns, magic-angle spinning nuclear magnetic resonance (MAS-NMR) technique and complex impedance analysis. All the compounds of La 9.33Si6-xAlxO 26-x/2□x/2 oxyapatites doped with Al3+ consist of a hexagonal structure with a P63/m space group. Lanthanum silicates doped with trivalent Al3+ have a higher conductivity than those without trivalent Al3+ at the Si4+ site. The extra oxygen O(4) atoms in site 2a (0, 0, 0.25) occupy channels running through the structure that are responsible for the high oxygen ion conduction. However, Al substitution seems to produce oxygen vacancies and create another pathway for oxide ions. The expansion of the channels (La(1)-O(4) distance) leads to an increase in the conductivity. For the best sample (x = 1), the conductivity observed was 5 × 10-3 S cm-1 at 750 °C. © 2014 Published by Elsevier B.V.This work was supported by Spanish Agency of International Cooperation (AECI-B/026856/09).Peer Reviewe

Structural aspects that enhance oxygen mobility in La9-2 x/3Mn0.5 REx□0.5-x/3(SiO4)6O 2 with RE = Ca, Sr and Ba

Oxyapatite-type silicates, La9-2x/3Mn 0.5 REx□0.5-x /3(SiO4)6O2 (x = 0.5; RE = Ca, Sr and Ba), were prepared by a high temperature solid-state reaction. Structure and unit-cell parameters were deduced from the analysis of X-ray powder diffraction data. Le Bail refinement of the X-ray powder diffraction data showed that the compounds have a hexagonal cell (P 63/m space group). The electrical properties of the materials were studied using the ac impedance spectroscopy technique. The extra oxygen O(4) atoms in site 2a (0, 0, 0.25) occupy channels running through the structure that are responsible for the high oxygen ion conduction. The presence of cation vacancies should enhance oxygen hopping along the c-axis; however, the analysis of the frequency dependence of ac conductivity suggests that oxygen motions are produced along three axes. The n-factor value of the dimensionality of the oxide ions increases with the conductivity when the size of RE cation decreases. © 2014 Elsevier B.V. All rights reserved.Peer Reviewe

Synthesis, structural characterisations, NMR spectroscopy, Hirshfeld surface analysis and electrochemical study of a new organic cyclohexaphosphate, (C6H7FN)4(Li)2(P6O18) (H2O)6

(C6H7FN)4(Li)2(P6O18) (H2O)6(I), a new organic cyclohexaphosphate, has been synthesized and grown at room temperature by an acid/base reaction between H6P6O18and 2-fluoroaniline as an organic template. The crystal structure of (I) was solved by single crystal X-ray diffraction analysis and it was found that the material belongs to triclinic system with space group P-1 and refined R-factor of 0.0520. Adjacent P6O18rings are connected via corner-sharing by LiO4tetrahedra, generating anionic [Li2P6O18·H2O]4-layers parallel to the (a, b) plane. The 2-fluoro-anilinium cations are inserted in the interlayer space and interact with the inorganic framework through N–H⋯O and O–H⋯O hydrogen-bonding interactions. Additional stabilization is provided by strong N–H⋯F and weak C–H⋯O hydrogen bonds. Hirshfeld surface analysis reveals the nature of intermolecular contacts of the title compound and their enrichment ratio reveals if they are over-represented. The crystal packing is a combination of strong electrostatic attractive interactions and of weaker hydrophobic contacts. The title compound was further characterized by FT-IR and NMR spectroscopies. Crystal symmetry is confirmed by31P magic angle spinning NMR and the vibrational absorption bands were identified by infrared spectroscopy. Electrical conductivity was studied using impedance spectroscopy and results showed that the conductivity at 150 °C was equal to 4.93 × 10−4S cm−1. It is therefore concluded that (C6H7FN)4(Li)2(P6O18) (H2O)6can be further used in lithium batteries